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CVE-2026-6733

undici: Undici: Response queue poisoning on reused keep-alive sockets can lead to incorrect response delivery.

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Severity

Low

Red Hat Product Security

3.7

CVSS 3.1

Review impact separately from score.

Published · June 18, 2026

Updated · October 27, 2026

Description

A flaw was found in undici. An attacker-controlled upstream server can exploit a vulnerability in Undici's HTTP/1.1 client, specifically related to response queue poisoning on reused keep-alive sockets. This allows the attacker to inject an unsolicited HTTP/1.1 response onto an idle socket. Consequently, when the client dispatches a new request on that socket, it may associate the injected response with the new request, leading to responses being delivered to unintended recipients or requests. This could result in a low impact on data integrity.

Statement

Low: A flaw in Undici's HTTP/1.1 client, as used in various Red Hat products, allows an attacker-controlled upstream server to inject unsolicited responses onto reused keep-alive sockets. This can lead to incorrect response delivery, potentially impacting data integrity, but requires a compromised server and active keep-alive connections.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

CVSS / CWE

CVSS 3.1 · 3.7
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CWE-940 · Improper Verification of Source of a Communication Channel